Frequency of words

Write a program to compute the frequency of the words from the input. The output should output after sorting the key alphanumerically.

Suppose the following input is supplied to the program:
New to Python or choosing between Python 2 and Python 3? Read Python 2 or Python 3.

Then, the output should be:
2:2
3.:1
3?:1
New:1
Python:5
Read:1
and:1
between:1
choosing:1
or:2
to:1

def frequency(input):
    freq = {}

    for word in input.split():
        freq[word] = freq.get(word, 0) + 1

    words = list(freq.keys())
    words.sort()

    for w in words:
        print(f'{w}:{freq[w]}')

frequency('New to Python or choosing between Python 2 and Python 3? Read Python 2 or Python 3.')

2:2
3.:1
3?:1
New:1
Python:5
Read:1
and:1
between:1
choosing:1
or:2
to:1